Male and female electrical terminal connector housings are often provided with releasable locking structure to lock them in their fully engaged position. The locking structure frequently takes the form of a flexible lock arm on one of the housings with a finger-operable release tab. This locking engagement is typically performed on automated assembly lines, and the housings must be checked to see if they are fully engaged. Accordingly, an additional part known as a "CPA" or connector position assurance element is sometimes used in the assembly process to detect or assure this locking engagement, indicating complete electrical connection of the terminals.
A first type of CPA element is pre-locked to one of the housings in association with the locking structure on that housing. When that housing is properly and fully engaged with the other housing, the CPA element is released from its pre-locked engagement with the one housing and can be withdrawn. The absence of this CPA or "detecting spacer" indicates a properly locked connector. An example of such a detecting spacer is disclosed in U.S. Pat. No. 5,330,369 to Nozaki et al.
A different type of CPA is shown in U.S. Pat. No. 5,120,255 to Kouda et al. A CPA in the form of a lock detecting slider is partway mated with a male connector, and the male connector is subsequently inserted into a female connector. When the male and female connectors are in complete electrical connection, the slider can be advanced to a lock indicating position where a mark on the slider can be viewed through an opening in the locking mechanism on the male connector.
A further type of CPA member is disclosed in U.S. Pat. No. 4,946,404 to Takenouchi et al. A CPA is mounted on a male connector in a pre-engaging position. A female connector releases flexible fingers on the pre-engaged CPA as the connectors mate, and the CPA member can then be further pushed to engage the female connector. The CPA then enhances the locking connection between the male and female connectors, while a base portion of the CPA prevents a male connector lock arm from being unintentionally released.
U.S. Pat. No. 5,030,127 to Blasko et al. discloses a male connector lock arm with a built-in release-preventing member in the form of a T-shaped thumb pad which prevents the connector arm from being accidentally disengaged by virtue of elevated guard surfaces on either side of the thumb pad. This lock arm does not use a separate CPA-type member as in the above-described patents.